This graphic shows the motions of the sun during his circuit. He moves from north to south and back in the course of a year. When the sun is at his northernmost points in the heavens, it is summer for those of us in the northern hemisphere. As he leaves us and moves down to the equinox (celestial equator), the weather gets cooler and it is autumn (autumnal equinox). When he is in the southernmost points of his circuit, it is winter. When he comes back up again to the equinox, the weather gets warmer and it is spring (vernal equinox). He contines northward and the weather gets hot.

In summary, the seasons are determined by the position of the sun during the course of his circuit from the one end of heaven to the other. Men call this circuit, the ecliptic. For us in the northern hemisphere, summer is when the sun is in the northernmost parts of our hemisphere; winter is when the sun is in the southern-most parts of his circuit.

Glossary:

ecliptic--sun's circuit through the heavens

summer solstice--sun at its highest (northernmost) point. Longest day of the year.

winter solstice--sun at its lowest (southernmost) point. Shortest day of the year.

equinox--portion of space corresponding to the equator; the celestial equator.